Nick Tate, 39, completed an Ironman challenge on Sunday, finishing the race in seven hours and 39 minutes.
Mr Tate, of Gipsy Lane, Wokingham, chose to raise money for The Elizabeth Foundation – which works with deaf children – plus Rotary, which gives money to a number of good causes.
He explained that a relative and a friend’s child were deaf so he knew the challenges faced by the families of deaf youngsters.
He said: “A friend from work, Mel Barlow, had a son, Lewis, in 2011, who was born profoundly deaf.
“Through her I learned about The Elizabeth Foundation.
“Mel and her husband were really pleased that I had thought of them and Lewis.”
Comprising a bike, cycle and swim totalling 70.3 miles, the race took place in Exmoor, winding around the Wimbleball Lake.
Signing up almost a year ago, he has been training relentlessly, including early morning bike rides and swims.
Mr Tate added: “I’ve done a few smaller things before but nothing like this!
“The event itself is something I’ve wanted to do for a while, it’s a personal challenge, but I really wanted to do something for charity.”
Aiming to raise £1,200, he has reached £230 and is still counting, but had all his friends and family behind him.
He said: “Everyone thought I was mad! I abstained from alcohol so I had two beers to celebrate after I finished.”
l To donate, visit www.justgiving.com/Nick-Tate2